Ethereum Classic is a decentralized platform that runs smart contracts: applications that run exactly as programmed without any possibility of downtime, censorship, fraud or third party interference. Ethereum Classic is a continuation of the original Ethereum blockchain - the classic version preserving untampered history; free from external interference and subjective tampering of transactions.

Ethereum Classic is an open-source, public, blockchain-based distributed computing platform featuring smart contract (scripting) functionality. It provides a decentralized Turing-complete virtual machine, the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes. Ethereum Classic also provides a value token called "classic ether", which can be transferred between participants, stored in a cryptocurrency wallet and is used to compensate participant nodes for computations performed. The classic ether token is traded on cryptocurrency exchanges under the ticker symbol ETC. Gas, an internal transaction pricing mechanism, is used to prevent spam on the network and allocate resources proportionally to the incentive offered by the request.

The Ethereum platform has been forked into two versions: "Ethereum Classic" (ETC) and "Ethereum" (ETH). Prior to the fork, the token had been called Ethereum. After the fork, the new tokens kept the name Ethereum (ETH), and the old tokens were renamed Ethereum Classic" (ETC). Ethereum Classic appeared as a result of disagreement with the Ethereum Foundation regarding The DAO Hard Fork. It united members of the Ethereum community who rejected the hard fork on philosophical grounds. Users that owned ETH before the DAO hard fork (block 1920000[7]) owns an equal amount of ETC after the fork.

Ethereum Classic passed a technical hard fork to adjust the internal prices for various opcodes of the Ethereum Virtual Machine (EVM) on October 25, 2016, similar to the hard fork committed by Ethereum a week previously. The purpose of the hard fork was a more rational distribution of payments for resource-intensive calculations, which led to the elimination of the favorable conditions for attacks that were previously conducted on ETH and ETC. A hard fork held in the beginning of 2017 successfully delayed the "bomb complexity" that was added to the Ethereum code in September 2015 with a view of exponentially increasing the complexity of mining and the process of calculation of new network units. The next hard fork is scheduled for late 2017 with the aim of changing the monetary policy with unlimited emissions to a system similar to Bitcoin.

Smart Contracts are computer systems that manage assets such as automatic teller machines and the Bitcoin system. Ethereum Classic is able to run many types of smart contracts. If Ethereum Classic smart contracts are not mainly financial, it makes more sense to emphasize their autonomy by referring to them as agents.